Neurotensinergic Excitation of Dentate Gyrus Granule Cells via Gαq-Coupled Inhibition of TASK-3 Channels.
Cereb Cortex
; 26(3): 977-90, 2016 Mar.
Article
em En
| MEDLINE
| ID: mdl-25405940
ABSTRACT
Neurotensin (NT) is a 13-amino acid peptide and serves as a neuromodulator in the brain. Whereas NT has been implicated in learning and memory, the underlying cellular and molecular mechanisms are ill-defined. Because the dentate gyrus receives profound innervation of fibers containing NT and expresses high density of NT receptors, we examined the effects of NT on the excitability of dentate gyrus granule cells (GCs). Our results showed that NT concentration dependently increased action potential (AP) firing frequency of the GCs by the activation of NTS1 receptors resulting in the depolarization of the GCs. NT-induced enhancement of AP firing frequency was not caused indirectly by releasing glutamate, GABA, acetylcholine, or dopamine, but due to the inhibition of TASK-3 K(+) channels. NT-mediated excitation of the GCs was G protein dependent, but independent of phospholipase C, intracellular Ca(2+) release, and protein kinase C. Immunoprecipitation experiment demonstrates that the activation of NTS1 receptors induced the association of Gαq/11 and TASK-3 channels suggesting a direct coupling of Gαq/11 to TASK-3 channels. Endogenously released NT facilitated the excitability of the GCs contributing to the induction of long-term potentiation at the perforant path-GC synapses. Our results provide a cellular mechanism that helps to explain the roles of NT in learning and memory.
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MEDLINE
Assunto principal:
Canais de Potássio
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Receptores de Neurotensina
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Giro Denteado
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Canais de Potássio de Domínios Poros em Tandem
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Subunidades alfa Gq-G11 de Proteínas de Ligação ao GTP
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Neurônios
Idioma:
En
Ano de publicação:
2016
Tipo de documento:
Article